function function_queue() {
	var pos = 0;
	var queue = arguments;
	return function() {
		if ( pos < queue.length )
		queue[pos++]();
	}
}

var scroll_x;
var scroll_y;

function scroll_map(direction) {
	switch(direction) {
		case 'west' :
			scroll_x = -16;
			scroll_y = -32;
			start_y += 1;
		break;

		case 'east' :
			scroll_x = 16;
			scroll_y = 32;
			start_y -= 1;
		break;

		case 'north' :
			scroll_x = 16;
			scroll_y = -32;
			start_x -= 1;
		break;

		case 'south' :
			scroll_x = -16;
			scroll_y = 32;
			start_x += 1;
		break;
	}

	run_scroll_sequence();
}

function run_scroll_sequence(x,y) {
	var q = function_queue(
		function(){move_tiles(q,start_x,start_y);},
		function(){draw_temp_tiles(q);},
		function(){hide_front_tiles(q);},
		function(){reset_front_tiles(q);},
		function(){copy_new_tiles(q);},
		function(){reveal_new_tiles(q);},
		function(){clear_temp(q);}
	);
	q();
}

function move_tiles(whenDone,iso_x,iso_y) {
	new Effect.MoveBy('tiles_center',scroll_x,scroll_y);
	new Ajax.Request('/game/tiles/' + iso_x + '/' + iso_y, {onComplete:function(t){eval(t.responseText)}});
	whenDone();
}

function draw_temp_tiles(whenDone) {
	draw_map(tiles,paths,'tiles_temp',apex_tile);
	whenDone();
}

function hide_front_tiles(whenDone) {
	Element.hide('tiles_center');
	whenDone();
}

function reset_front_tiles(whenDone) {
	$('tiles_center').innerHTML = '';
	$('tiles_center').style.left = '0px';
	$('tiles_center').style.top = '0px';
	whenDone();
}

function copy_new_tiles(whenDone)	{
	$('tiles_center').innerHTML = $('tiles_temp').innerHTML;
	whenDone();
}

function reveal_new_tiles(whenDone)	{
	Element.show('tiles_center');
	whenDone();
}

function clear_temp(whenDone) {
	$('tiles_temp').innerHTML = '';
	whenDone;
}